Tạp chí khoa học số 2005-09-09

Table of Contents 9 Septem ber 20 0 5 Volume 309 Number 5741 The Pow er of W alking Tow ard Cheaper Genom es As the Hum an Brain Evolves Nanosprings Take Form RESEARCH Poor Man's Sequencing? * Toward Magnetic Spintronics * Perovskite Preservation * Frustrating Magnetism * Turning Its Stripes * More Makes More * Puzzling Brain Genes * The Message Is the Messenger * Patchwork Plant Life * Power Walking * Freeing p53 * Plague Targets Its Victims * Chemistry and Quantum Computation * Preindustrial Methane Emissions * Making and Breaking the Gradient 1645 CHEMISTRY: Move Away or Stay Put * MOLECULAR BIOLOGY: Me Instead of U * BIOMEDICINE: Mergers and Acquisitions * CLIMATE SCIENCE: Poring over the Past * BIOCHEMISTRY: Some Like It Hot * CHEMISTRY: Oxides as Reductants * STKE: Neuropeptide-Mediated Receptor Trafficking 1651 D. A. Allwood, G. Xiong, C. C. Faulkner, D. Atkinson, D. Petit, and R. P. Cowburn 1688-1692. Toshiyuki Hayakawa, Takashi Angata, Amanda L. Lewis, Tarjei S. Mikkelsen, Nissi M. Varki, and Ajit Varki 1693. FT Tao Huang, Henrik B󳵌hlenius, Sven Eriksson, Fran󳵄ois Parcy, and Ove Nilsson 1694-1696. Satoru Nakatsuji, Yusuke Nambu, Hiroshi Tonomura, Osamu Sakai, Seth Jonas, Collin Broholm, Hirokazu Tsunetsugu, Yiming Qiu, and Yoshiteru Maeno 1697-1700. Pu Xian Gao, Yong Ding, Wenjie Mai, William L. Hughes, Changshi Lao, and Zhong Lin Wang 1700-1704. Alán Aspuru-Guzik, Anthony D. Dutoi, Peter J. Love, and Martin Head-Gordon 1704-1707. 3 Christian Holzapfel, David C. Rubie, Daniel J. Frost, and Falko Langenhorst 1707-1710. 2 James Heath, Edward Ayres, Malcolm Possell, Richard D. Bardgett, Helaina I. J. Black, Helen Grant, Phil Ineson, and Gerhard Kerstiens 1711-1713. I D. F. Ferretti, J. B. Miller, J. W. C. White, D. M. Etheridge, K. R. Lassey, D. C. Lowe, C. M. MacFarling Meure, M. F. Dreier, C. M. Trudinger, T. D. van Ommen, and R. L. Langenfelds 1714-1717. Patrick D. Evans, Sandra L. Gilbert, Nitzan Mekel-Bobrov, Eric J. Vallender, Jeffrey R. Anderson, Leila M. Vaez-Azizi, Sarah A. Tishkoff, Richard R. Hudson, and Bruce T. Lahn 1717-1720. Nitzan Mekel-Bobrov, Sandra L. Gilbert, Patrick D. Evans, Eric J. Vallender, Jeffrey R. Anderson, Richard R. Hudson, Sarah A. Tishkoff, and Bruce T. Lahn 1720-1722. n in a Biodiversity Hot Spot Andrew M. Latimer, John A. Silander, Jr., and Richard M. Cowling 1722-1725. Lawrence C. Rome, Louis Flynn, Evan M. Goldman, and Taeseung D. Yoo 1725-1728. Jay Shendure, Gregory J. Porreca, Nikos B. Reppas, Xiaoxia Lin, John P. McCutcheon, Abraham M. Rosenbaum, Michael D. Wang, Kun Zhang, Robi D. Mitra, and George M. Church 1728-1732. Jerry E. Chipuk, Lisa Bouchier-Hayes, Tomomi Kuwana, Donald D. Newmeyer, and Douglas R. Green 1732-1735. Susan R. Schwab, Jo󳵀o P. Pereira, Mehrdad Matloubian, Ying Xu, Yong Huang, and Jason G. Cyster 1735-1739. Melanie M. Marketon, R. William DePaolo, Kristin L. DeBord, Bana Jabri, and Olaf Schneewind 1739-1741. W. T. Geng, J S. Wang, and G. B. Olson 1677. Masatake Yamaguchi, Motoyuki Shiga, and Hideo Kaburaki 1677. COMMENTARY Burton G. Bennett 1649. Women Making Strides in Big Pharma Catherine D. Strader, Satwant K. Narula, and Jean E. Lachowicz ; The Importance of Origins? Kamyar Kalantar-Zadeh, Mohammad Navab;, Varshasb Broumand, Salomeh Keyhani, Berhooz Broumand;, and Wasim Maziak ; Firearms, Violence, and Self-Protection Gary D. Kleck;, Jeffrey B. Bingenheimer, Robert T. Brennan, and Felton J. Earls ; The Sight of Violence and Violent Action Narendra G. Mehta ; Mistakes in a Map Lei Fu; and Donald Kennedy ; Corrections and Clarifications 1673. T. Kuiken, F. A. Leighton, R. A. M. Fouchier, J. W. LeDuc, J. S. M. Peiris, A. Schudel, K. St󳵌hr, and A. D. M. E. Osterhaus 1680-1681. Donald MacKenzie 1678-1679. Amalia M. Issa 1679. 1679. Timothy Hla 1682-1683. Brian A. Korgel 1683-1684. Karen H. Vousden 1685-1686. II Arthur D. Kuo 1686-1687. NEWS John Travis 1656-1659. Carolyn Gramling 1657. At Last, a Supportive Parent for Saturn's Youngest Ring Richard A. Kerr 1660. Adrian Cho 1660. Dennis Normile 1661. ction Michael Balter 1662-1663. John Bohannon 1663. Jennifer Couzin 1664-1666. Jennifer Couzin 1665. Richard A. Kerr 1667. Robert Irion 1668-1669. 1742. EXHIBITS: Catching Rays * IMAGES: Microbes in Bloom * DATABASE: Proteomics Central * EDUCATION: A Universal Primer * TOOLS: Physics Blog Trail 1655 Committee: Nurture DOD Tissue Bank * Roberts's AIDS Memo Criticized * First Woman Head for Pasteur * Ban on Papers Lifted * Consumers Nano-Cautious 1659 Out in The Cold * Plying an Ancient Trade Route * Surf 'n' Turf * Oldest Body to Science * Deaths * Pioneers * Jobs * Data Point 1670 III Toward Magnetic Spintronics At present, microelectronic technology relies on the flow and control of electron charge in lithographically fabricated circuits, but electrons also have a quantum- mechanical spin that could be exploited to create logic circuits. Many approaches to “spintronics” have focused on semiconducting materials, but others have investigated magnetic materials. Allwood et al. (p. 1688; see the cover) discuss a particular proposed architecture for magnetic logic circuits that harnesses the movement of magnetic domain walls, which are the boundaries between oppositely aligned magnetic regions. Basic logic functions and nonvolatility have been demonstrated with simple combinations of magnetic nanowires. Perovskite Preservation The primary mineral in Earth’s lower mantle is per- ovskite (Fe,Mg)SiO 3 , but the amount of perovskite will depend on the overall composition. For example, sub- ducted oceanic crust may be predominantly perovskite. The remixing or homogenization of these regions is af- fected greatly by the diffusion of major cations—Fe, Mg, and Si—at the high temperatures of Earth’s man- tle. Holzapfel et al. (p. 1707, published online 28 July 2005) have now measured the interdiffusion of Fe and Mg in perovskite in experiments at high temperature and pressure. Diffusion is so slow that homogenization, even on very small scales, is not possible on time scales as long as the age of the Earth. Thus, disparate regions in Earth’s mantle will be preserved unless they are mixed mechanically. Frustrating Magnetism Long-range magnetic ordering that develops as a ferromagnet or antiferromagnet is cooled can be suppressed by introducing defects. Theoretical work has suggested that suppression could also occur on geometrically frustrated lattices in which the pairwise coupling of the spins cannot be met, such as on a triangular lat- tice. Nakatsuji et al. (p. 1697) now report on the realization of one such bulk triangular lattice, NiGa 2 S 4 , and present evidence that antiferromagnetic order can be completely suppressed, even to the lowest temperatures. The simple lattice structure could also be used to probe other cooperative phenomena, such as quantum criticality and second- order phase transitions. Turning Its Stripes Under conditions of vapor-solid growth at high temperatures, zinc oxide can form nanobelts, and the dipoles set up by the opposite charges of the two faces of these ultrathin ribbons can drive the form of spirals or even closed loops. Gao et al. (p. 1700; see the Perspective by Korgel) now report that prolonged annealing at very high temperatures (1400°C) in an inert atmosphere can cause the belts to widen and twist into long helices. High- resolution transmission elec- tron microscopy shows that the nanobelts are converted into a superlattice of alternat- ing stripes that run the length of the belt and that orient their c axes at right angles to one another. This change re- duces the polarity difference between the two faces, and a small twist between adjacent stripes drives the formation of the helix. More Makes More The effect of increasing CO 2 levels on forest soils has been studied by Heath et al. (p. 1711), who tracked the move- ment of carbon using stable carbon isotopes. High concen- trations of CO 2 stimulated increased photosynthesis and plant growth but also caused a decline in the amount of carbon sequestered in the soil that was not affected by addition of soil nutrients. Microbial respiration in soils could provide a large positive feedback on the rate of increase of the concentration of atmospheric CO 2 , and raise the possibility that the future rise in atmospheric CO 2 concentrations could be higher than expected. Puzzling Brain Genes Mutations in the genes Microcephalin and ASPM (abnormal spindle-like microcephaly associated) in humans correlate with microcephaly. Although the affected brains are much reduced in size, the detailed architecture of the brain remains. A gene related to Microcephalin is under positive selection pressures in the evolution of primate lineages leading up to humans. Evans et al. (p. 1717) and Mekel-Bobrov et al. (p. 1720) have now analyzed the evolution of Microcephalin and ASPM genes in modern humans and find that both genes also respond as though under positive selection (see the news story by Balter). Thus, unknown advantages have encouraged the rapid spread of these gene variants throughout the human population. www.sciencemag.org SCIENCE VOL 309 9 SEPTEMBER 2005 1645 edited by Stella Hurtley and Phil Szuromi 1.5 cm 2 T HIS W EEK IN CREDITS (TOP TO BOTTOM): SHENDURE ET AL.; NAKATSUJI ET AL.; CONTINUED ON PAGE 1647 Poor Man’s Sequencing? Cheaper sequencing technologies are a high priority for many applications, including resequencing projects to study genomic variation. Shendure et al. (p. 1728, published online 4 August 2005; see the 5 August news story by Pennisi) bring the $1000 genome a step closer with a nonelectrophoretic approach, based on amplification of DNA fragments and enrichment followed by ligase-based sequencing on immobilized beads and imaging using an epifluorescence micro- scope. The procedure was roughly ninefold cheaper than conventional sequencing, with greater accuracy and speed. Other laboratories should be able to build their own equivalent sequencing system using off-the-shelf equipment. Published by AAAS www.sciencemag.org SCIENCE VOL 309 9 SEPTEMBER 2005 The Message Is the Messenger As the days lengthen in spring and summer, plants sense the hours of daylight in their leaves and respond by initiating flowering at the top of the plant, in the shoot apex. The identity of the signal that is transported from the leaf to the apex has been unclear (see Wigge et al., Abe et al., and the Perspective by Blázquez in the 12 August issue). Huang et al. (p. 1694, published online 11 August 2005) now show that local expression of the gene FT (FLOWERING LOCUS T) in a single leaf is sufficient to cause flowering by transfecting a heat-inducible form of FT into Arabidopsis plants. Within 6 hours of stimulating a single leaf, FT messenger RNA (mRNA) appears in the shoot apex, where it stimulates transcription of genes involved in flowering and of FT itself. Although other elements may be involved, FT mRNA is an important component of the floral stimulus that moves from leaf to shoot in response to increases in day length. Patchwork Plant Life The fynbos Mediterranean shrubland of the Cape Floristic Region of South Africa is one of the most species-rich plant habitats on Earth. Latimer et al. (p. 1722) find that the region’s high plant diversity is associated with low migration rates and with speciation rates higher than those in the most diverse tropical forests such as Amazon rain forest. The local species abundance patterns in fynbos is a mosaic made up of centers of locally endemic plants, with little migration among them and relatively few universally rare species, unlike the well-mixed tree communities of Amazon upland rain forest. Power Walking Even highly rational people can be seduced by the prospect of getting something for nothing. Rome et al. (p. 1725; see the Perspective by Kuo) have devised a machine that recovers energy that is otherwise wasted. They have modified a backpack by introducing a vertically moveable weight that rises about 5 centimeters with each step and then turns a gear as it falls. This device can be used to recover some of the energy used in carrying supplies—a load of 38 kilograms produces up to 7 watts of electricity, compared with about 20 milliwatts from shoe-based devices. Although many refinements must be made, such an apparatus could generate power during journeys beyond the reach of power grids, reducing the need for heavy batteries. Freeing p53 The tumor suppressor protein p53 functions to promote cell death or apoptosis in response to stress. It acts by modulating gene expression in the nucleus and by interacting with regulatory proteins in the cytoplasm that control apoptosis. Chipuk et al. (p. 1732; see the Perspective by Vousden) provide evidence for a mechanism by which these actions of p53 may be coordinated. The product of one p53 target gene is a protein known as PUMA (p53 up-regulated modulator of apoptosis). In cells exposed to DNA-damaging agents, interaction of PUMA with the antiapoptotic protein Bcl-xL appears to cause release of p53 that was previously bound to Bcl-xL.The released p53 may then be free to activate the cytoplasmic events that lead to apoptosis. Plague Targets Its Victims So-called type III secretion machines are used by Yersinia and other Gram-negative bacteria to inject proteins directly into target cells. The injected effector substrates are essential factors for the pathogenesis of infectious disease. Marketon et al. (p. 1739, published online 28 July 2005) now show that Yersinia pestis, the agent responsible for plague, selects macrophages, dendritic cells, and neutrophils for type III injection; B and T lymphocytes are rarely selected as targets. During plague, type III injection leads to the rapid depletion of immune cells from the spleen with a concomitant increase in the relative amount of injected cells. The selection of host cells with innate immune functions disables the immune system and leads to rapid progression of this invariably fatal illness. CONTINUED FROM 1645 THIS WEEK IN CREDIT: HUANG ET AL. Published by AAAS EDITORIAL www.sciencemag.org SCIENCE VOL 309 9 SEPTEMBER 2005 1649 T his year marks the 60th anniversary of the atomic bombings of Hiroshima and Nagasaki that ended World War II. Whatever the historical circumstances at the time, the bombings were tragic experiences for the cities and for the many who sustained severe blast, heat, and radiation injuries. The horrifying consequences prompted efforts to control nuclear arms proliferation, an issue that still remains a top foreign policy priority. The cities have made remarkable recoveries, and the survivors maintain indomitable spirits, allowing themselves to serve as a reference point for modern radiation safety in the world. As the size of this population of survivors grows smaller, we must not lose a sense of responsibility to support them and to investigate and understand the health consequences engendered by these events. This week, the World Health Organization and Nagasaki University hold a joint meeting to review the latest information on radiation-induced effects in the atomic bomb survivors and to consider the implications of this research for international policies. Since the bombings, follow-up investigation of the health of the survivors has continued. Early in 1947, the U.S. government founded the Atomic Bomb Casualty Commission, managed by the U.S. National Academies with cooperation from the Japan National Institute of Health. In 1975, the United States and Japan became equal funding partners, creating the Radiation Effects Research Foundation to continue the study. The main epidemiological investigation of atomic-bomb survivors is the Life Span Study. It is based on a large cohort from a general population of both sexes and all ages, encompassing a wide range of accurately known doses and incorporating accurate recordings of disease incidence and mortality. The original cohort had 120,000 survivors. This included large representative groups of young people, who are the people currently being monitored. At present, about 43% of the Life Span Study cohort is still alive. A major finding is that radiation-associated cancers continue to occur as a small enhancement of the background rates. Through the year 2000, 8% of the deaths from solid cancers in individuals exposed to radiation could be attributed to radiation. Many of these radiation-related cancer deaths were recorded in recent years of monitoring, indicating that as the survivors age and enter the cancer-prevalent period in their lives, significant additional radiation-related deaths can be expected. Radiation-associated deaths from leukemia (46% of all leukemia deaths) peaked within 10 years of the bombings and no longer occur. Noncancer deaths are also showing a small but significant relationship, with radiation exposure making up 1.4% of these deaths. That finding requires explanation of the underlying mechanisms. Genetic effects are being investigated, although health effects in children of the survivors have not been apparent. About 94% of the second generation is still alive. It is essential to continue the lifetime study for its full duration, for which continued cooperation from the survivors and support from the U.S. and Japanese government sponsors will be necessary. Its investigations of health consequences are heavily relied on to establish guidelines for human health and safety policies throughout the world. The survivor data feature prominently in international scientific reviews of radiation effects, such as those of the United Nations. The International Commission on Radiological Protection uses the risk evaluations to derive recommendations for radiation protection that are adopted by most countries. Reports on the Biological Effects of Ionizing Radiation from the U.S. National Academies also rely heavily on survivor data and have not only figured into formulating safety guidelines but are relevant to many current issues of concern such as worker and public protection, worker and survivor compensation, cleanup efforts, accident response, and counterterrorism preparedness. A further 5-year funding agreement between Japan and the United States will be put in place this year, ending concerns regarding continued funding of this unique project. But a very important phase of examining the younger exposed cohorts and children of the survivors is just beginning, with a dominant time frame being the 2000–2040 period. We have a responsibility to continue this study, to contribute to the welfare of those affected, to understand and quantify the effects, and to provide a scientific basis for radiation protection and medical policies worldwide. We should not lose the memory of these events or lessen our resolve to understand their effects even after 60 years. Burton G. Bennett Burton G. Bennett is retiring chairman of the Radiation Effects Research Foundation, Hiroshima and Nagasaki, Japan. 10.1126/science.1117108 Responsibility Beyond 60 Years CREDIT:TIME & LIFE PICTURES/GETTY IMAGES Published by AAAS www.sciencemag.org SCIENCE VOL 309 9 SEPTEMBER 2005 1651 MOLECULAR BIOLOGY Me Instead of U Small interfering (si)RNAs and micro (mi)RNAs play a central role in RNA silencing phenom- ena in which RNAs comple- mentary to the si/miRNA are targeted for cleavage and destruction, translational silencing, or are (presumably) used as markers for directing heterochromatin formation. Much is known about the bio- genesis of si/miRNAs, but what happens to them afterward? In Arabidopsis, the HEN1 protein, implicated in RNA silencing, has been shown to add a methyl group to the 3′ ends of miRNAs. Results from Li et al. show that Hen1 has a much wider scope, methylating many Arabidopsis siRNAs at their 3′ ends, too. In the absence of HEN1, the unmethylated miRNAs and siRNAs have several uridine (U) residues added to their 3′ ends, indicating that methylation interferes with uridylation. Intriguingly, it is the sense strand of the miRNA:miRNA* duplex that preferentially has a U tail added, hinting that the addition might occur after passage through the RISC complex, when the antisense miRNA* strand has already been jettisoned.The authors propose that methylation may stabilize small RNAs, a specula- tion supported by the previous observation that cleaved mRNA targets have also been observed to be U-tailed. — GR Curr. Biol. 15, 1501 (2005). BIOMEDICINE Mergers and Acquisitions Many people living with diabetes for an extended time eventually develop a complica- tion called diabetic neuropathy, a form of nerve damage that affects the extremities with symptoms that range from tingling and numbness to severe pain.Although many hypotheses have been proposed to explain how this nerve damage arises, the underlying mechanisms remain poorly understood. A new study identifies an unexpected cellular culprit. From an analysis of rodent models,Terashima et al. find that diabetic neuropathy is accompanied by an aberrant fusion of bone marrow–derived (BMD) cells to neurons in the sciatic nerve and dorsal root ganglion. The fusion, which appears to involve a distinct subset of BMD cells that are marked by inappropriate expression of proinsulin, disrupts calcium handling in the neurons and triggers their premature death. The authors speculate that the diabetic state likely induces inappropriate gene expression in the BMD cells, producing molecules (such as tumor necrosis factor– α) that may be toxic to neurons and to the hybrid cells.Although BMD cells are often viewed in a favorable light for their potential therapeutic applications in repairing tissue damage, this study suggests that in certain contexts these cells may in fact be harmful. — PAK Proc. Natl. Acad. Sci. U.S.A. 102, 12525 (2005). CLIMATE SCIENCE Poring over the Past The concentration of CO 2 in the atmosphere is under- stood to be a primary controller of climate, and high values are thought to be the main cause of a number of extended warm periods over the geological history of Earth. Additionally, atmospheric CO 2 exerts a fundamental influence on the carbonate chemistry of the ocean, due to the solubility of CO 2 in seawater, and therefore on calcifying marine organisms.A direct record of atmospheric CO 2 concentration is available for less than the past 1 mil- lion years, so earlier periods must be studied by modeling or via proxies. Haworth et al. use meas- urements of the density of stomata, the pores through which gas exchange occurs in plant leaves, in an extinct conifer to estimate the par- tial pressure of atmospheric CO 2 during the mid- Cretaceous.This technique takes advantage of the obser- vation that stomatal density is negatively correlated to the concentration of CO 2 in the air.They find that CO 2 was between 560 and 1200 parts per million over that period, values that fall on the low side of the range of previous estimates based on other techniques and are compatible with other evi- dence for relatively cool mid- Cretaceous climates. — HJS Geology 33, 749 (2005). EDITORS ’ CHOICE H IGHLIGHTS OF THE RECENT LITERATURE edited by Gilbert Chin Hybrid cells expressing BMD and neuronal markers. CREDITS: (TOP) DAMERON ET AL., NANO LETT. 10.1021/NL050981J (2005); (BOTTOM) TERASHIMA ET AL., PROC.NATL. ACAD. SCI. U.S.A. 102, 12525 (2005). CONTINUED ON PAGE 1653 CHEMISTRY Move Away or Stay Put Microcontact printing (µCP) of thiols on gold surfaces makes it feasible to create intricate patterns quickly and at low cost, but one limitation of this method in many applications is that the thiol molecules tend to diffuse into the bare regions of the gold surface. Trying to restrict the spreading by backfilling the bare spots in a follow-up step can blur pattern boundaries through prolonged expo- sure to solvent. Dameron et al. show that the preadsorption of 1-adamantanethiol (AD) on gold surfaces creates a well-ordered but weakly bound layer that can be displaced by long-chain thiols, such as 1-decanethiol, that are transferred to the surface with a µCP stamp. By tuning the concentration of alkanethiols on the stamp and the contact time, patterns can be formed without the problem of lateral mixing of the adjacent self-assembled monolayers (SAMs). — PDS Nano Lett. 10.1021/nl050981j (2005). Displacement printing with an alkanethiol-inked stamp. Published by AAAS BIOCHEMISTRY Some Like It Hot Ever since atomic-resolution models of enzymes from thermophilic organisms appeared a decade ago, one question has been how these macromolecules are able to function (that is, remain flexible) while maintaining their integrity (that is, remain stable) at temperatures approaching 100ºC. Some of the explanations offered are an increase (relative to their mesophilic cousins) in the number of salt bridges and/or hydrogen bonds, a tighter packing of the hydrophobic core, and a higher percentage of amino acids incorporated into α helices and β sheets. Berezovsky and Shakhnovich have carried out unfolding simulations on matched proteins from mesophiles and thermophiles, and performed comparative genome-based analysis of mesophilic and thermophilic bacteria and archaea.They find two solu- tions for thriving at high tempera- tures: make pro- tein structure more compact by optimizing relatively weak interactions globally or engineer a few strong interac- tions into the sequence.They suggest that archaeal thermophiles (Pyrococcus furiosus) were favored by starting off long ago with more designable proteins that could be adapted to the primordial hothouse, whereas bacterial thermophiles (Thermotoga maritima) that entered hot environments later on were forced to reinforce their proteins with staples (salt bridges or perhaps disulfides). — GJC Proc. Natl. Acad. Sci. U.S.A. 102, 12742 (2005). CHEMISTRY Oxides as Reductants High-valent metal-oxo compounds are often used to mediate or catalyze oxida- tions of organic substrates. Nolin et al. have pursued the counterintuitive approach of using a rhenium-oxo com- plex to catalyze reduction. Rather than transferring oxygen to a hydrocarbon, the Re=O group facilitates hydride transfer from a silane to an imine. Unlike most catalysts used for this type of reaction, the Re complex is already in a high oxida- tion state and therefore fully stable in the open atmosphere. By appending a chiral bis(oxazoline) derivative to the Re center, the authors achieved enantioselective reductions of a broad range of aromatic imines under air at room temperature, with yields of 50 to 90% and very high enantiomeric excesses (92 to >99%). The imine nitrogens were protected with phosphinyl groups that could then be removed hydrolytically after reduction. The catalyst selectively reacts with the imine group even in the presence of esters and olefins, leading to a variety of chiral amines of potential use as pharmaceutical precursors. — JSY J.Am. Chem. Soc. 10.1021/ja050831a (2005). www.sciencemag.org SCIENCE VOL 309 9 SEPTEMBER 2005 CONTINUED FROM 1651 EDITORS’ CHOICE A home for ther- mophiles;Vulcano Island, Italy. Neuropeptide-Mediated Receptor Trafficking Opioid receptors on pain-sensing neurons mediate the inhibitory effects of opiates on pain. The δ-opioid receptor, which is sorted into large dense-core vesicles (LDCVs) that carry secreted neuropeptides, is inserted into the membrane in response to opioid agonists or neuronal firing. Guan et al. noted that, in dorsal root ganglion neurons containing substance P, δ-opioid receptors colocalized with the neurotransmitter substance P in LDCVs, but in mice lacking preprotachykinin A gene, which encodes substance P and other tachykinin peptides, the receptors were absent from the vesicles. By expressing different portions of the substance P precursor, the authors determined that the δ-opioid receptor sorting signal was in the substance P domain and that sorting into LDCVs depended on the interaction of the signal with the third extracellular loop of the opioid receptor. Stimulus-dependent membrane insertion of the δ-opioid receptor was attenuated in preprotachykinin A–knockout mice, and both δ-opioid receptor–mediated spinal analgesia and morphine tolerance were eliminated. Thus, these results suggest an intriguing link between pain pathways (substance P) and analgesia (opioid receptor). — EMA Cell 122, 619 (2005). H IGHLIGHTED IN S CIENCE’ S S IGNAL TRANSDUCTION KNOWLEDGE ENVIRONMENT CREDITS: JOCELYNE DIRUGGIERO Published by AAAS www.sciencemag.org SCIENCE VOL 309 9 SEPTEMBER 2005 1655 TOOLS Physics Blog Trail Cyber scribes could be praising or blasting your latest paper, but how would you know? If you post your work on the physics preprint server arXiv, now you can find out what colleagues are saying about it. The archive has begun displaying “trackbacks,” notifications blog- gers often send out when they mention a paper or site. The trackbacks appear as links below the paper’s abstract, allowing anyone to see who wrote what about the findings. Read more about the feature at arxiv.org/help/trackback. arxiv.org NETWATCH edited by Mitch Leslie CREDITS (TOP TO BOTTOM): NINA GUNDE-CIMERMAN AND POLONA ZALAR; JIM SPADACCINI/IDEUM; NASA/JPL IMAGES Microbes in Bloom A briny desert lake and sediment 5000 meters below the ocean surface are just two of the unlikely places where microbes prosper. The Microbiological Garden,tended by Heribert Cypionka of the University of Oldenburg in Germany, shows off the bugs dwelling in these exotic environments and in habitats closer to home. The site features more than 20 photo essays on microbial topics.You can tag along on bug-hunting expeditions, learn how to isolate luminescent bacteria from herring, and observe the bugs that inhabit the scum on the surface of a stagnant pool. Some microbes make the gallery because of their beauty, such as these yeast spores (Emericella stellamaris;above) that resemble flowers. www.microbiological-garden.net DATABASE Proteomics Central Sequencing genomes is a breeze compared with proteomics, identifying and describing the welter of proteins that a cell, tissue, or organism harbors.PRoteomics IDEntifications database (PRIDE), a new site hosted by the European Bioinformatics Institute, helps proteomics researchers by serving as a central storehouse for experimental results. So far, the site holds data from more than 1600 studies, including fresh findings from the Human Proteome Organization’s survey of the proteins in human plasma and in platelets (Science, 21 November 2003, p. 1316). Search the clearinghouse by species and tissue to find out which proteins and peptides each study nabbed.You can also deposit your findings in the database, which accepts results from liquid chromatography/ mass spectrometry and gels. www.ebi.ac.uk/pride/ EDUCATION A Universal Primer By opening Windows to the Universe, stu- dents can compare comets that frequent the solar system, study a climate change tutorial, or learn about a star’s life.The encyclopedia of earth and space science from the University Corporation for Atmospheric Research in Boulder, Colorado, furnishes material from elementary school to high school levels, although many of the pages would be suitable for beginning college classes. The site’s many galleries range from famous scientists to solar system objects such as the asteroid Ida (above), which is big enough to boast its own moon. Windows to the Universe also lets readers explore the interplay between science and culture by browsing poems, myths, and art about space and Earth. www.windows.ucar.edu/windows.html Send site suggestions to netwatch@aaas.org. Archive: www.sciencemag.org/netwatch EXHIBITS Catching Rays Tracking the seasons was so important for the Maya of Central America and many other ancient cultures that they designed buildings and settlements around the sun’s annual movements. Visit some of the sun cities of North America at Traditions of the Sun, sponsored by NASA.The site’s historic and modern photos, time-lapse series, video, and other multimedia whisk you off to Chaco Culture National Historic Park in New Mexico.Watch sunlight creep over the great house of Pueblo Bonito on the summer solstice, or take a virtual reality tour of the kiva at Casa Rinconada, which aligns with the points of the compass. From there you can zoom to Mayan cities on Mexico’s Yucatan Peninsula such as Chichén Itzá and Dzibilchaltún. The House of the Seven Dolls (above) in Dzibilchaltún provided a spectacular visual effect for a key Mayan ceremony. On the spring and fall equinoxes, the sun rises directly behind the building and shines through the archway. www.traditionsofthesun.org Published by AAAS . Hiroshima and Nagasaki, Japan. 10.1126 /science. 1117108 Responsibility Beyond 60 Years CREDIT:TIME & LIFE PICTURES/GETTY IMAGES Published by AAAS www.sciencemag.org SCIENCE VOL 309 9 SEPTEMBER 2005 1651 MOLECULAR. in false color from the Hubble Space Telescope). Published by AAAS www.sciencemag.org SCIENCE VOL 309 9 SEPTEMBER 2005 ScienceScope 1661 First Woman Head for Pasteur PARIS—Cell biologist Alice. Culture, Sports, Science, and Technology (MEXT) included the projects in its annual budget submission (Science, 2 September, p. 1473). But they can’t claim the pot until the end of a new science budget